This invention relates to the cleaning of surfaces, especially embossing surfaces or the surfaces of printing plates used for example, in the production and converting of paper products and/or polymeric film products. The invention is especially useful for cleaning steel embosser rolls used to emboss paper for tissue and towel products. This invention, however, is also useful in the cleaning of other surfaces, e.g. printing plates, rubber marrying rolls, embossing rolls, etc.
Process surfaces used to produce polymeric films, tissue and towel paper products, accumulate by products of the process such as glue deposits, residual paper fiber, and residual polymeric material on the process surfaces. This build up of by products may create defects in the finished product. This is especially true when steel embosser rolls are used to create deep embossing in paper towel products.
The prior art teaches the use of cleaning processes and cleaning brushes to remove this build up on processing surfaces. For example, the prior art teaches the use of water or steam delivered via an internal manifold on a cleaning brush to prevent or remove contamination build up on surfaces. In particular U.S. Pat. No. 6,804,856, Udall, discloses an apparatus for cleaning a surface, comprising a brush, the brush being in the form of a drum wherein steam is used in association with the drum, and the brush may be disposed within a hood with an extraction system. These standard type brushes, however, cause several problems. The steam or water may quickly saturate isolated areas of the brush causing excessive sling. Furthermore, because the water or steam is not evenly distributed to the brush bristles, the water or steam will not be evenly distributed to the process surface. In addition, excessive water may also build up where the inner manifold lines up with the orifices of the core leaving adjacent orifices dry. Both of these deficiencies lead to less effective or ineffective cleaning via the brush.
Furthermore, unreliable prior art cleaning methods sometime require removal of the contaminated process surfaces from the production line for cleaning by hand. This is expensive, time consuming, and inconvenient. Moreover, removal of plates and embosser rolls may also require use of temporary or replacement rolls/plates while the cleaning is underway. Again this is time consuming and expensive.
The present invention overcomes the above described deficiencies of the prior art for cleaning these process surfaces. The present invention provides superior cleaning of process surfaces through the arrangement and size of apertures, wherein the apertures are arranged in a staggered multi helical pattern comprising from about 3 to about 15 helixes; and wherein the peripheral wall has a surface area ratio of from about 6 to about 30.